: a chemical element of the noble gas group with atomic number 2 that is found especially in natural gases and used chiefly for inflating airships and balloons, as a coolant for superconductors, and as a component of inert atmospheres (as in welding)
—often used before another noun
helium balloons
helium gas
see Chemical Elements Table
Examples of helium in a Sentence
Recent Examples on the Web
What was expected to be a weeklong trip to the ISS instead turned into an over nine-month stay after the capsule suffered helium leaks and thruster failures.
—
Leah Sarnoff, ABC News, 20 Mar. 2025
But for officials at the U.S. space agency, the difficult choice became necessary when engineers uncovered a slew of helium leaks and thruster issues when Boeing's Starliner reached the space station.
—Eric Lagatta, USA TODAY, 20 Mar. 2025
Starliner, though, suffered thruster failures and helium leaks in its propulsion system.
—Richard Tribou, Orlando Sentinel, 19 Mar. 2025
Wilmore and Williams saw their June 2024 ride out, a Boeing Starliner capsule, return without them, because of a faulty propulsion system and helium leaks to boot.
—The Editorial Board, Chicago Tribune, 19 Mar. 2025
See All Example Sentences for helium
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Leah Sarnoff, ABC News, 20 Mar. 2025
But for officials at the U.S. space agency, the difficult choice became necessary when engineers uncovered a slew of helium leaks and thruster issues when Boeing's Starliner reached the space station.
—Eric Lagatta, USA TODAY, 20 Mar. 2025
Starliner, though, suffered thruster failures and helium leaks in its propulsion system.
—Richard Tribou, Orlando Sentinel, 19 Mar. 2025
Wilmore and Williams saw their June 2024 ride out, a Boeing Starliner capsule, return without them, because of a faulty propulsion system and helium leaks to boot.
—The Editorial Board, Chicago Tribune, 19 Mar. 2025
See All Example Sentences for helium
Articles Related to helium
Cite this Entry
“Helium.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/helium. Accessed 25 Mar. 2025.
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Medical Definition
helium
noun
he·li·um
ˈhē-lē-əm 
: a light colorless nonflammable gaseous element found especially in natural gases and used chiefly for inflating airships and balloons, for filling incandescent lamps, and for cryogenic research
—symbol He
see Chemical Elements Table
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